Energy

GRADE

Forms of Energy

You have heard of the word "energy" all your life.. You need to eat vegetables
to grow strong and have "energy". You need to go to bed early so you will
have "energy" in the morning to go to school. Energy is the ability to do
work. Energy is everywhere in nature-sunlight, wind, water, plants, and
animals. We use energy everyday.

Two kinds of energy are kinetic and potential. Kinetic energy is the energy of motion. Potential energy is stored energy. A good example of kinetic and potential energy is a frog
leaping. A frog sitting on a lily pad is an example of potential energy. The frog leaping is an example of kinetic energy.

Different forms of energy are

light

chemical

mechanical

heat

electric

atomic

sound

All these forms of energy can be broken down either into kinetic or potential.

Law of Conservation of Energy- Energy can neither be created nor destroyed.
Energy is always changing from one kind to another. The total energy of
an object never changes.

(narrative and pictorial description of potential and kinetic energy, use
math)

Energy of Reactions

All chemical reactions require energy to occur. The rate of a reaction or
how fast it occurs depends on:

the number of particles,

the temperature, and

the presence of any catalysts.

1. PARTICLE CONCENTRATION

If you add more soap to water, the more bubbles will form. The higher the
concentration of particles in a reaction, the faster it will go. Concentration
is the number of particles in a volume of space. Look at the boxes below,
which one will the reaction occur faster.

2. TEMPERATURE

Temperature is an indicator of heat. If you want your water to boil faster,
you increase the temperature by turning the knob on high. Most reactions
go faster at higher temperatures. Remember the difference between water
vapor particles and ice particles. Water vapor particles move about more
rapidly then ice particles. Ice particles are moving in slow motion compared
to the gas particles. (animation)

3. CATALYSTS

Catalysts are substances that help make a reaction go faster. Scientists
believe adding a catalyst to a reaction increases the number of particle
collisions. A collision is when something hits something else with great
energy. Some examples of catalysts are enzymes. There are enzymes in your mouth that help speed up the procees of digestion.

Energy and chemical reactions

Chemical reactions require energy. This energy can either be released or
absorbed. Chemical reactions that give up heat energy are called exothermic
reactions. The prefix "exo" means "out" and "therm" means "heat". Burning
wood in a fireplace gives off heat to warm you up. Most chemical reactions
are exothermic. Endothermic reactions absorb heat. "Endo" means "in" and
"thermic" means "heat". Baking powder in dough causes bread to rise. It
absorbs the heat from the oven to form carbon dioxide gas.